In the past, various types of case-handling machines have been developed. Case-handling machines include machines for erecting cases, machines for sealing cases and machines for placing inserts in cases, plus various combinations thereof. For example, some case-handling machines both erect cases and, then, partially seal the erected cases. Other case-handling machines merely seal cases. In some machines, sealing is accomplished using an adhesively coated tape. In other machines, an adhesive is applied directly to the major and/or minor flaps of the case to be sealed. In some machines, both the bottom and the top of the cases are sealed after the case has been loaded with the object or objects to be stored in the case. In such machines, the case is partially assembled and, then, loaded prior to entering the machine. More specifically, the case is erected and the bottom major flaps folded over the bottom minor flaps. The top major and minor flaps of the case are left upstanding. The objects are loaded into the case as the case is supported on a suitable supporting medium, such as a conveyor. Thereafter, the case is conveyed to the case sealing machine, which simultaneously seals the bottom flaps of the case as the top flaps are being folded and sealed. The present invention relates to the latter type of case sealing machines, i.e., case sealing machines having the capability of simultaneously sealing both the top and bottom flaps of cases, or sealing either the top or the bottom flaps of cases, as desired. More specifically, the present invention relates to case sealing machines having the capability of simultaneously sealing both the top and bottom flaps of random size cases, or sealing either the top or the bottom flaps of such cases, as desired.
In the past, case sealing machines designed to seal both the top and/or bottom of cases (regardless of whether the cases were required to be of fixed size or could be randomly sized) have been either manually controlled or semi-automatically controlled by an electromechanical mechanism that includes a plurality of sensing switches actuated by lever arms impinged on by the case, as the case is moved through the machine. Manually controlled machines are undesirable because they are both slow and labor-intensive. Semi-automatically controlled electromechanical machines have a number of other disadvantages. First, because sealing machines use glue to seal cases, glue is often spattered. Because of their location, glue is ocassionally spattered on sensing switches, resulting in incorrect machine operation. When this occurs, the machine must be shut down and corrective cleaning and/or repair steps taken.
Another major disadvantage of prior art electromechanically controlled case sealing machines is the difficulty attendant to changing the manner of operation of such machines. Usually a switch arm and/or a timing wheel peg must be repositioned in order to change the operation of one of the machine mechanisms (e.g., glue heads, kicker, case-aligning rails, etc.) Such changes require the services of tools and mechanics, and result in machine down-time. Machine down-time is undesirable for two reasons--the costs of the related machine adjustment and/or repairs; and, resultant idle time of the machine operator and employees filling the cases being sealed by the machine.
Thus, there is a need for case sealing machines that use a minimum number of position-sensing switches, yet can be easily programmed to selectively seal the top, bottom, or both the top and bottom of a case as the case is moved through the machine. In particular, there is a need for such a case sealing machine that is suitable for sealing the top, bottom or both the top and bottom of random size cases as such cases are moved through the machine. The present invention is directed to providing such a machine.